Engineers from the University of Bristol have developed a new robotic arm, which they state, will improve the way we interact with computers, robots, and other devices using an affordable, highly scalable, haptic force feedback system. The engineers built the Mantis system using readily available off-the-shelf hardware, making it easy to scale and control.
Mantis is a highly scalable, light, and affordable haptic feedback system that allows users to create accurate, multiform, easy-to-use force feedback platforms. (📷: University of Bristol)
“Theoretically; the Mantis could be built and used by anyone upwards from a secondary school student. Not only that, the Mantis can be built for 20 times less the expense of the market equivalent because it uses components, including brushless motors, that cost significantly less than high-fidelity equivalents that are often confined to research labs.”
The Mantis system was created using a series of brushless Zhuhai hengliyuan X8308S DC motors (over coreless motors), which are combined with an admittance control scheme, that provides the system lower transmission ratios while matching the force capabilities of more expensive platforms such as 3D Systems’ Phantom haptic device. The admittance control is handled using custom force sensors the engineers designed, which features an inner loop admittance controller running at 10kHz, and an outer loop interface layer chugs along at 1kHz
The Mantis controller is based on an Arm Cortex-M4 equipped with three SPI bus ports, three three-phase digital power amplifier stages, three ADC channels, and programmable logic hardware (for control signals). It also packs Ethernet, USB 2.0, four RS485 serial bus channels, and offers a DFU bootloader for easy firmware upgrades. While the picture above shows four 3D-printed arms, the Mantis system can be outfitted with one or as many as needed, and at any length, short or long.
As far as applications go, the Mantis system can be used for gaming and virtual reality, among many others where haptic feedback can be integrated. What’s more, Mantis isn’t limited to a lab setting, as it can be designed as a wearable as well, allowing users to implement mobile applications for the platform. The engineers state they will upload the plans to Mantis at some point soon.